1. Field of the Invention
The present invention relates to a direct-type light-emitting diode (LED) backlight module and, more particularly, to a direct-type LED backlight module using a local dimming technology.
2. Description of the Prior Art
A direct-type LED backlight module is disposed behind a display panel, such as a liquid-crystal display panel, which produces no light of its own. The direct-type LED backlight module is configured to provide external light for the display panel to produce a visible image. Moreover, the direct-type LED backlight module may further use a local dimming technology to reduce power consumption and increase the contrast ratio of the image.
The conventional direct-type LED backlight module using the local dimming technology has a basic structure including a back bezel, a reflector, LED lightbars, a diffuser and at least one local dimming control board. The back bezel has a first surface and a second surface opposite each other. Each LED lightbar includes a printed circuit board (PCB) and LEDs disposed on the PCB. The LED lightbars are disposed on the first surface of the back bezel, and the LEDs disposed on the LED lightbars are uniformly arranged relative to the display panel. The diffuser is disposed above the LED lightbars and configured to diffuse light emitted from the LEDs to form a surface light source with a uniform brightness. The reflector is disposed between the back bezel and the LED lightbars and configured to reflect the light emitted from the LEDs toward the diffuser to raise the efficiency of the light emitted from the light source. Each local dimming control board is disposed on the second surface of the back bezel and configured to adjust the brightness of the LEDs within a specific zone to implement local dimming. Therefore, each local dimming control board needs cables to connect with the corresponding LED lightbars. These cables needs to be installed from the back bezel second surface where each local dimming control board is disposed to the back bezel first surface where the LED lightbars are disposed, resulting in high wiring cost and more assembly time.